KANSAS CITY, Mo, -- At least a dozen people are dead following a shooting at a California bar.

According to the Ventura County Sheriff's Office, Ian Long opened fire at the Borderline Bar and Grill in Thousand Oaks. The victims include Sgt. Ron Helus, one of the officers who exchanged gunfire with Long. Sheriff Geoff Dean said upon re-entry, officers found Long dead in the bar's office.

Dean says Long, a Marines veteran, wasn't a stranger to law enforcement. In April, a crisis intervention team went to his house for a disturbance call. Dean said Long was somewhat irate and behaving a little irrationally.

Specialists cleared Long and determined he did not qualify for an involuntarily mental health hold.

Many officers in the metro are trained as crisis intervention team members. This week, there was a TRI-CIT training for more local officers to learn how to respond to mental health clients. Part of the training involved actors simulating calls and real officers responding then getting evaluated on their reactions.

"Things that may seem bizarre to you -- if you learn about them, the situation may not get as heightened," said Kristen Rivera, a school resource deputy for the Clay County Sheriff's Department. "You can calm it down before it gets to that point. You can calm it down before it gets to that point."

Peggy Gorenflo is the community mental health liaison for the Clay County agency.

"It does look different than a lot of other calls," Gorenflo said.

There are 29 other liaisons like her in the state. After a CIT call, they're the officer's next point of contact.

"That's one of the reasons why we train is because we don't want those situations to happen," Gorenflo said, referring to the mass shooting overnight in Thousand Oaks.

Although Long was cleared, Gorenflo said follow-ups are still important. That's why they go through all the CIT reports that Missouri officers file.

"We review through them, and we offer services," Gorenflo said. "We call, we sometimes do follow-up visits. We go with the officers and do follow-up visits and check on the individuals and see if there's anything else they might need."